Rectifier protective system



March 9, 1937.

0. K. MART] 2,073,113

RECTIFIER PROTECTIVE SYSTEM Filed Aug. 20, 1952 mnim:

Mme mag Patented Mar. 9, 1937 UNITED STATES PATENT OFFICE RECTIFIERPROTECTIVE SYSTEM Application August 20,

Claims.

*This inventionrelatesto improvements in protective systems and more.particularly to protective systems for electron discharge devices of thearcing type.

;; it is. well known that proper operation of electrendischarge devicesis obtained only when gas or vapor within such device is maintainedwithin ecertain limits of pressure. In devices'pf the vaciuum: type,thespaceshould be highly evacuated 1 randdn devicesof the, gas or vaportype, tlie gas or thewapor should be maintained at apress ure notexceedingamredetermined value. The presence of undesired gasesoryaporsorthe occurrence of undesired pressures in the operati g gas or vapor arenot readily cetect dflQQ e the pressure within the device is not; unifoi m, consequently a pressure gage connected at one .point of thedevice gives no indication of the prfifilres at other points thereof.The indications of pres:- sure gages are particularly deficient duringthe so-called forming or seasoning of gas or vapor arcing devices, whenlarge amounts of gas are evolved from the different parts of the deviceand more particularly from the electrodes thereof.

The degree to which a device of the above character is seasoned isdetermined by the amount of gas evolving from the electrodes, and theproper .operation of such device is determined by the pressure in thepath of discharge where it is usually difiicult or entirely impossibleto insert a pressure measuring device. Under the infiuence of someaccidental factors, electron discharge devices are also apt to fail intheir valve action whereupon an internal short circuit or backfireoccurs. Means have been heretofore developed ior interrupting suchbackfires shortly after the occurrence thereof so as to minimize theirrestructive effect on the electrodes and their disturbing effect on thesystem connected there- 4 with. Such means, however, do not detectimpending backfires and hence cannot prevent their occurrence.

It has been found that, in a device of the gas or vapor type, when thepressure in the space within the device is different from that at whichsatisfactory operation may be expected, the discharge or are becomesunstable and introduces a rapidly varying resistance in the circuit ofthe device. Such variations of the resistance in the circuit produceoscillations at different frequencies including modulated oscillationswithin the range of frequency used for radio broadcasting purposes. Suchoscillations in turn produce electromagnetic waves which may be detectedin the immediate vicinity of the device. It was also 1932, Serial No.629,663

found that, before an electron discharge device backfires, the are alsooscillates for a short period of time and likewise leads to theproduction of electromagnetic waves. It should not be concluded thatbackfires are due solely or even par- 5 tially to the presence offoreign gases within the device, as they may be due to some other causealso leading to the production of oscillations. By introducing suchoscillations into the input circuit of a radio receiving set, it ispossible to obtain currents from the output circuit of such set whichgive an indication of any disturbance and permit disconnection of thedevice before a ,backfire has occurred as a result of such disturb-.ance.

It is accordingly one object of the present inventlonto provide acontrol system for electron dischargedevices in which oscillations inthe circuit of the device may be detectedlamplified and transformedintoaudible or visible signals. 20

Another object of the present invention is to provide a control systemfor electron'dis'char'ge devices in which undesired value sof thegas'orvapor pressure within the device are measured by means of the magnitudeof oscillations "in the 25 circuit of the device.

Another object of the present invention is to provide a control systemfor electron discharge devices in which disturbances leading tobackfires within the device are detected through measurement ofoscillations in the circuit of the device.

' Another object of the present invention is to provide a control systemfor electron discharge devices in which the device is automatically madeinoperative upon occurrence of oscillations in the circuit thereof.

Objects and advantages other than those above set forth will be apparentfrom the description when read in connection with the drawing, in which:

Fig. l diagrammatically illustrates one embodiment of the presentinvention applied to an electron discharge device of the metallic vaporarcing type operable as an electric current rectiher, in which a radioreceiving'set is used for measuring the oscillations within the deviceand for disconnecting such device upon occurrence of oscillations of apredetermined value;

Fig. 2 diagrammatically illustrates a modified embodiment of the presentinvention differing from that shown in Fig. 1 in the means used formaking the electron discharge device inoperative upon the occurrence ofoscillations above a predetermined limit in the circuit thereof.

Referring more particularly to the drawing by of frequencies.

characters of reference, reference numeral 6 designates an electrondischarge device of the metallic vapor arcing type shown as connectedfor alternating current rectification, between an alternating currentsupply line 1 and a direct current output line 8, 9. Device 6 isconnected with line I by means of a transformer having a primary windingH and a secondary Winding |2 comprising a plurality of star connectedportions severally connected with the anodes l3 of device 6. As shown inFig. l, winding II is connected with line by means of a circuit breaker|4 maintained in the closed position by means of a latch l6 which may bereleased upon energization of a trip coil l7. One of the conductors ofthe output line is provided with a second circuit breaker I 8 maintainedin its closed position by a latch l9 which may be released uponenergization of a trip coil 2|. Trip coils I1 and 2| may be energizedfrom a battery 22 having its circuit completed over contacts 23 uponclosure of a relay 24 connected as will be described hereinafter.

The oscillations in the circuit of the device are transmitted to theinput circuit of a radio receiving set of a suitable type generallyrepresented at 27. Such transmission is obtained by electrostatic orelectromagnetic coupling means between the circuit of the device and theinput circuit of the receiver set such as a transformer 26. Receivingset 21 is shown as comprising a set of filters 28 for the purpose oftransmitting, through the circuits of the set, oscillations of only onefrequency or only within a predetermined range The receiving set isshown as also comprising one stage of radio frequency amplification 29,a detector 3| and one stage of audio frequency amplification 32. Theoutput terminals of the receiving set may be connected with a number ofcontrol devices such as relay 24, an ammeter 33 and a loud speaker orhorn 34. The device 6 may be evacuated or maintained at anypredetermined pressure by a suitable pump 36.

In operation, assuming that line 1 is energized and that circuitbreakers I4 and 8 are closed, anodes l3 will sequentially carry currentreceived from line for rectification into direct current supplied toline 8, 9 as is Well known in the art. Upon the occurrence of disturbingpressures within the device or of any other phenomena apt to producebackfires therein, the circuit of the device will oscillate. Suchoscillations will generally be at frequencies within the range of thefrequencies used for radio broadcasting purposes, modulated atfrequencies Within the audible range of frequencies. Such oscillationsinduce currents in transformer 26 and are transmitted to filter 28.Filter 28 permits application of voltages at one frequency or within apredetermined range of frequencies to audio amplifier 29 where suchoscillations are amplified to be further transformed into audiofrequency oscillations in detector 3|, such oscillations then beingamplified in amplifier 32 with the result that currents at such audiofrequencies are supplied to meter 33, relay 24, and audible signal 34.Meter 33, therefore,

continuously gives a visible indication of the amplitude of theoscillations within device 6, and signal 34 gives a continuous audibleindication thereof. Such oscillations may reach a value causing theproduction of excessive losses within the device or may be conducive tothe occurrence of backfires, whereupon relay 24 closes its contacts 23,thereby energizing trip coils I! and 2| and opening circuit breakers l4and I8. If the oscillations in the device were caused by the presence ofexcessive amounts of gas therein, the circuit breakers may be reclosedonly after such gases have been removed by means of pump 36. If thedisturbance is produced by some transient accidental cause, the devicemay generally be reconnected immediately with lines I and 8, 9.

In the embodiment shown in Fig. 2, device 6 is provided with controlelectrodes 36 for purposes of controlling the operation of the severalanodes i3 thereof. Control electrodes 36 receive a negative potentialwith respect to the cathode of the device from a battery 3? and alsoreceive alternating potentials from secondary winding 39 of atransformer having a primary winding 4| energized from line '5. Controlelectrodes 36 thus sequentially receive positive potentials with respectto the cathode, thereby permitting operation of the associated anodesI3. As is well known in the art such connection permits regulation ofthe output voltage of the device. are inserted in the circuits ofcontrol electrodes 36 to limit the fiow of current therethrough. Winding4| is connected with line I by means of a circuit breaker 42 retained inits closed position by latch 43 which may be released upon energizationof a trip coil 44. Trip coil 44, in the present embodiment, is shown asoperable from battery 22 through contacts 23 of relay 24 while circuitbreakers i4 and I8 are provided only for manual operation. In thepresent embodiment, the input circuit of radio receiver 2'! is shownconnected with an antenna 30 extending into the casing of device 6, andwith a ground as at 35.

In operation, device 6 operates as in the embodiment of Fig. l, thesequential energization of anodes l3, however, being controlled by theenergization of control electrodes 36. Upon occurrence of a disturbancewithin device 6, oscillations are produced therein and transmitted bymeans of antenna 30 to the input circuit of radio receiver 21. In thepresent embodiment also audio frequency currents are obtained and aresupplied to meter 32, relay 24, and loud speaker 33. When such currentsreach a predetermined magnitude, relay 24 closes its contacts 23 therebycausing circuit breaker 42 to disconnect winding 4| from line Winding 39no longer being energizedfrom winding 4|, all control electrodes 36receive only a negative potential from battery 31, thereby causingdevice 6 to cease to function. If the disturbance was caused by thepresence of foreign gases in the device, such gases must be removed bypump 36 whereupon circuit breaker 42 may be reclosed to permit furtheroperation of the device. If the oscillations were produced due to sometransient accidental cause, circuit breaker 4-2 may generally bereclosed immediately after its opening.

It will be understood by those skilled in the art that although thepresent protective system is illustrated only as applied to electrondischarge devices connected for operation as electric currentrectifiers, such system may be applied without modifications of itsessential parts to such devices when operable as direct current inverts,D. C. voltage converters, frequency converters or circuit interrupters.

Although but two embodiments of the present invention have beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

Resistances 38 It is claimed and desired to secure by Letters Patent:

1. In a protective system for electron discharge devices, an alternatingcurrent line, a transformer connected with said line, an electrondischarge device of the arcing type connected with said transformer andsubject to creation of high fre,- quency oscillations therein uponoccurrence of abnormal conditions therein, a direct current lineconnected with said transformer and. with said device, and indicatingmeans inductively connected with said direct current line operableresponsive to and in dependence upon the occurrence of said highfrequency oscillations within said device.

2. In a protective system for electron discharge devices, an alternatingcurrent line, a transformer connected with said line, an electrondischarge device of the arcing type connected with said transformer, adirect current line connected with said transformer and with saiddevice, and a radio receiving set coupled with said device for detectingand indicating oscillations occurring in said device upon the occurrenceof conditions tending to cause disturbances therein.

3. In a protective system for electron discharge devices, a plurality ofelectric current lines, an electron discharge device of the arcing type,a plurality of circuit breakers controlling the connection of saiddevice with said lines, means for detecting and amplifying theoccurrence of oscillations in said device tending to cause the occurrence of disturbances therein, and means operated by the first saidmeans to cause operation of said circuit breakers.

4. In a protective system for electron discharge devices, a plurality ofelectric current lines, an electron discharge device of the arcing type,a plurality of circuit breakers controlling the connection of saiddevice with said lines within a predetermined range of frequencies,means for detecting and amplifying the oscillations produced in saiddevice and tending to cause the occurrence of disturbances therein, andmeans operated by the first said means to cause operation of saidcircuit breakers.

5. In a protective system for electron discharge devices, a plurality ofelectric current lines, an electron discharge device of the arcing type,a plurality of circuit breakers controlling the connection of saiddevice with said lines, magnetic means associated with each of the saidcircuit breakers to control the opening thereof, a source of currentarranged for connection with said magnetic means, means for detectingand amplifying oscillations produced in said device and tending to causethe occurrence of disturbances therein, and a relay operated by thesecond said means to control the connection of said source of currentwith said magnetic means upon the occurrence of oscillations within apredetermined range within said device.

6. In combination with a vapor electric valve converting apparatuscomprising an anode, a cathode, a control electrode, and a conductivemember in contact with the ionized vapor of the apparatus, a controltransformer for exciting said control electrode to control the energytransmitted by said apparatus, and means responsive to the potentialbetween said conductive member and said cathode for modifying themagnetization of said transformer to modify the operation of saidapparatus.

7. The combination with an electric valve comprising a casing forming anevacuated chamber having an anode and a cathode supported therein andforming spaced electrodes for the flow of current of unidirectiontherebetween, of a control electrode associated with said anode, meansfor exciting said control electrode to control the said fiow of current,and means comprising a conductive member supported within said casingwithin the ionized vapor therein operable responsive to an abnormalcondition within said valve, for controlling the operation of the firstsaid means.

8. The combination with an electric valve comprising a casing forming anevacuated chamber having an anode and a cathode supported therein andforming spaced electrodes for the flow of current of unidirectiontherebetween, of a control electrode associated with said anode, meanscomprising a transformer for exciting said control electrode to controlthe said fiow of current, and means comprising a conductive membersupported within said casing within the ionized vapor therein operableresponsive to an abnormal condition within said valve, for controllingthe operation of the first said means.

9. The combination with an electric valve of the vapor type comprising acasing forming an evacuated chamber having an anode and a cathodesupported therein and forming spaced electrodes for the flow of currentof unidirection therebetween, of a control electrode associated withsaid anode, means for exciting said control electrode to control saidfiow of current, means comprising a relay operable to control the firstsaid means, and means comprising a conductive member supported withinsaid casing in contact with the ionized vapor therein operableresponsive to an abnormal condition within said valve, for controllingthe operation of the second said means.

10. The combination with an electric valve comprising a casing formingan evacuated chamber having an anode and a cathode supported therein andforming spaced electrodes for the flow of current of unidirectiontherebetween, of a control electrode associated with said anode, meansfor exciting said control electrode to control the said flow of current,and means comprising a conductive member supported within said casingwithin the ionized vapor therein operable responsive to an abnormalcondition within said valve tending to cause reverse direction of flowof said current, for controlling the oper-- ation of the first saidmeans.

OTHMAR K. MARTI'.

